Laine Stump <la...@laine.org> schrieb am 9:17 Mittwoch, 15.Januar 2014:
On 01/15/2014 10:05 AM, Karoline Haus wrote:
Good morning,
>
>
>I'm using libvirtd on Gentoo.
>This is libvirt version: 1.1.3.1
>
>
>I have trouble starting a VM using virsh start $vm. I do this as root, because
>as non-root user it did not work at all (especially it failed attaching to the
>networks). So, when I run the command (with sudo), I get the following error
>in libvirtd.log:
>
>
>2014-01-15 07:51:00.423+0000: 16158: warning : qemuDomainObjTaint:1573 :
>Domain id=5 name='vader' uuid=f5b8c05b-9c7a-3211-49b9-2bd635f7e2aa is tainted:
>high-privileges
>
This usually means that libvirt has been configured to run the qemu
process as root, which introduces the possibility that a guest
exploiting some theoretical security exploit in qemu could gain
control of the host system. Normally libvirt installations will by
default be configured to run the qemu-kvm process as user qemu, with
all privilege bits cleared; either gentoo's default install of
libvirt doesn't set things up this way, or you or someone else has
modified /etc/libvirt/qemu.conf to change the "user" and "group"
parameters to "root".
To fix this problem, edit /etc/libvirt/qemu.conf and either comment
out those two parameters (if they aren't already commented out), or
change them to set both user and group to "qemu" (assuming that
gentoo follows the standard of adding a "qemu" user when installing
libvirt), then restart the libvirt service and try starting the
guest again.
Note, however, that this is a *warning*, not an error, so the guest
should still be starting up and running. If not, then there should
be some subsequent error message in the log (and/or look at the end
of /var/log/libvirt/qemu/${vm}.log for error messages from qemu)
2014-01-15 07:51:00.428+0000: 16158: error : virDBusCallMethod:1173 : Launch
helper exited with unknown return code 1
>
>
>At the same time I get an error in /var/log/messages which seems related:
>Jan 15 07:51:00 dbus[15845]: [system] Activating service
>name='org.freedesktop.machine1' (using servicehelper)
>Jan 15 07:51:00 dbus[15845]: [system] Activated service
'org.freedesktop.machine1' failed: Launch helper exited with
unknown return code 1
>
>
>Anyone ever seen this issue? I have no idea where to look for errors because
>the message don't really tell me much.
The problem is that the part that tells you something is pretty
short: "Domain [...] is tainted: high-privileges"
I have tried to execute the qemu-kvm command on the command line directly and
that worked immediately.
Because when you run qemu-kvm from the commandline, it is being run
as root. libvirt goes to great lengths to enable running the
qemu-kvm process as "unprivileged" as possible, so that any
potential security exploits in qemu-kvm will be as limited as
possible in the damage they can do. Any operation that requires
elevated privileges (e.g. creating a tap device to hook up the
guest's networking, modifying the selinux labelling of various
resources) is done by libvirt, which passed open file descriptors to
the newly created resources to a qemu-kvm process that has been
created running as an unprivileged user, with all privilege bits
reset and pretty much all system resources limited by cgroups.
So the problem must be in libvirt.
Well, in your system's libvirt configuration anyway.
The problem is not the "Domain is tainted" issue. I have set the privileges
back to user libvirt (I had set it to root myself in libvirtd.conf) and the
problem still exists.
2014-01-15 10:42:34.963+0000: 16162: info : libvirt version: 1.1.3.1
2014-01-15 10:42:34.963+0000: 16162: error : virDBusCallMethod:1173 : Launch
helper exited with unknown return code 1
You can see now the "Domain is tainted" error (warning!) doesn't show anymore,
but the domain still does not start. The only error message I get is the one
above.
In /var/log/messages I still get:
Jan 15 10:42:34 dbus[15845]: [system] Activating service
name='org.freedesktop.machine1' (using servicehelper)
Jan 15 10:42:34 dbus[15845]: [system] Activated service
'org.freedesktop.machine1' failed: Launch helper exited with unknown return
code 1
I think the problem is in org.freedesktop.machine1. For some reason, that
service cannot be activated, but I don't understand why.
Any help would be greatly appreciated.
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